Method of coating



Oct. 6, 1931. E. CHAPPELL METHOD OF COATING Filed May 3l, 1928 3Sheets-Sheet 2 Oct. 6, 1931. E. CHAPPELL.

METHOD OF COAT ING 3 Sheets-Sheet 3 Filed May 3l, 1928 Patented Oct. 6,1931 UNITED STATES PATENT OFFICEV EUGENE L. CHAJPPELL, OF MCKEESPORT,PENNSYLVANIA, ASSIGNOR T NATIONAL TUBE COMPANY, A CORPORATION OF NEWJERSEY METHOD OF COATING Application led May 31,

the inner surface of the pipe by drawing a' mandrel through the pipe, orof spreading' a layer of cement in the pipe by whirling the pipecentrifugally. v

In the drawings: Figure 1 is a plan view of an apparatus used incarrying out the method of this inn vention.

Figure 2 is a side elevation thereof. Figure 3 is an end elevationthereof. Figure 4 is a detail view illustrating the suspension memberused to suspend the coata5 ed pipes from the conveyer.

Figure 5 is a sectional detail illustrating the manner of mounting thepipe to be internally coated.

'Figure 6 is a. view similar to Figure 5, showing the modified couplingused to mount pipes to be coated on both the inside and outsidesurfaces, or when large .diameter pipes are to be vcoated on the insideonly.

In carrying out the method of applying a coating to the interior surfaceof a pipe, the pipe A is threaded or otherwise secured in the couplingmember 2 of the coating apparatus and extends vertically in theapparatus. An inclinedvoverflow trough 3 is then fitted over the upperend of the pipe to be coated, with its discharge end positioned over ahopper 4 adapted to receive the overflow of coating material.

The coupling` member 2 is connected to a coating supply conduit 5 whichleads from a coating cylinder 6 adapted to contain a supply of thecoating material. The hopper 4 is also-connected to the cylinder 6 by aconduit 7, so that additions of cement may be readily fed into thecylinder 6 from the hop- 1928. Serial No. 281,789.

per 4, and also the overiiow from the pipes being coated may also bereturnedto the cylinder.

A valve 8 is provided in the conduit 5 adjacent the cylinder 6, and asecond valve 9 is provided in the conduit 7 adjacent the cylinder 6.When it is desired to draw the overllow or new char e of cement from thehopper 4 and conduit 7, the valve 9 is opened and the valve 8 is closed,while when the pipe is being coated the valve 9 is closed and the valve8 is opened.

`A fluid pressure cylinder L() is provided for operating the plunger ofthe coating cylinder 6. A

A 'setting chamber 12 is arranged to one side of the coating apparatuswith its one end adjacent `the pipe being coated. The chamber 12 is ofgreater height than the pipe to be coated so that the coated pipes maypass therethrough in a vertical position. The end walls of the chamber12 are slotted, as at 1 4, to permit the coated pipes to enter and leavethe chamber. v

A conveyer mechanism, consisting of a pair of endless chains 15 havingcross-bars 16 therebetween, is mounted above the chamber 12, and thecoated pipes are adapted to be removably suspended from the conveyorcross-bars 16 by hooks 17 which have threaded sleeve portions 18 adaptedto be threaded on the upper ends of the coated pipes. The conveyermechanism is adapted to move the pipes slowly through the chamber v12,which chamber may or may not have a relatively hjlgh temperature watersaturated atmosere. p After the pipe to be coated has been mount-- ed inthe coupling member 2, and the overflow trough 3 has been mounted overthe 90 upper end of the pipe, the 'luid pressure cylinder 10 will beoperated to movethe plunger of the coating cylinder 6 forwardly so as toexpel the plastic cement from the cylinder 6 through the conduit 5 andthe pipe A to be coated. The cylinder 6 is of such size that it willcontain an excess of coating material over the volume necessary to iillthe pipe being coated. Therefore, when the plunger of the cylindercompletes its forward stroke, 10o

the coating cement will have completely filled the pipe A and overfiowedinto the trough 3.

After the pipe has been completely filled with coating cement, thecylinder 10 will be reversed so as to reverse the plunger of thecylinder 6. This will create a vacuum in the cylinder 6 which willwithdraw the excess cement from the pipe back into the cylinder,

leaving the pipe A coated with a substantially impervious coating ofplastic cement having an even thickness throughout its length.

After the excess plastic cement has been removed from the pipe, theoverflow trough 3 will be removed and one of the hooks 17 threaded onthe upper end of the pipe. The hook 17 will then be engaged ,with one ofthe cross-bars 16 of the conveyer and the pipe will be conveyed in avertical position through the drying or setting chamber 12, so as toset'the coating.

After the coating has set, the pipe will be removed from the conveyerand the coating may be cured in any of the usual manners of curingcement.

In case both the inside and outside surfaces of the pipe are to becement coated a modified form of coupling 2 is substituted for thecoupling 2. The coupling 2a is of materially larger diameter than thepipe to be coated and a large diameter pipe 50 is threaded in thecoupling to form an enclosing tubular casing for the pipe to be coated.The coupling 2a is provided with a centrally arranged sleeve 2b,supported by spider members 2, and the pipe to be coated-is threaded 1nthis sleeve 2.

The coating cement is forced through the conduit 5 and coupling 2a inthe usual manner from the cylinder 6 and, instead of being confined tothe interior of the pipe to be coated, it also is forced up within'thelarge diameter pipe or casing 50, so that when the excess cement iswithdrawn the outside and inside surfaces of the pipe are coated.

The same class of coupling fitting 2L may be conveniently used when itis desired to coat the inside surfaces of large diameter ipes, in whichcase the pipe to be coated will be threaded in the coupling proper and amandrel having a closed lower end will be threaded in the sleeve 2", sothat the coating cement need only fill the space between the mandrel andthe interior surface of the pipe. By using this method with largediameter pipe less cement need be handled.

If desired, the excess cement coating material may be permitted to drainor flow out of the pipes by gravity, although this procedure will beslower and less efficient than when the excess cement is forced out ofthe pipes by suction.

It will also be understood that while this method is particularlyadapted for applying mineral cement coatings to pipes, it is not limitedspecifically thereto, since other coatings may be advantageously appliedby the specific method of this application, which consists in forcing anexcess of the coating material through the pipe and then withdrawing theexcess.

While I have shown and described one form of apparatus for carrying outmy invention, it will be understood that I do not wish to be limited tothe use of such apparatus, since various other forms of apparatus may beused to carry out the method of this application without departing fromthe scope thereof as defined in the appended claims.

I claimy 1. The method of coating the surfaces of metal pipe withmineral cement which consists in forming an excess body of the cement ina plastic state over the pipe surface to be coated while said pipe is ina substantially vertical position, then removing the excess cement fromsaid surface, and then setting said coating in a water saturatedatmosphere at a relatively high temperature and while said pipe is stillmaintained in a substantially vertical position.

2. The method of coating the surfaces of metal pipe with mineral cementwhich consists in forcing an excess of plastic cement in a confinedflow-body over the surface to be coated, and then withdrawing the excesscement from the pipe by suction.

3. The method of coating the surfaces of metal pipe with a flowablemixture of mineral cement, which consists in forcing an excess of saidcement through the pipe in a continuous flow-body while said pipe ismaintained in a vertical position, then applying a vacuum to the lowerend of said pipe to withdraw the excess from the interior of said pipeleaving a coating of substantially equal thickness over the entireinterior surface of said pipe, and then maintaining said pipe in aVertical position until said coating is set.

4. The method of coating the surfaces of metal pipe with a ilowablemixture of mineral cement, which consists in forcing an excess of saidcement through the pipe in a continuous flow-body while said pipe 1smaintained in a vertical position, then applying a vacuum to the lowerend of said pipe to withdraw the excess cement from the interior of saidpipe leaving a coating of substantially equal thickness over the entireinterior suri face of said pipe, and then maintaining said pipe 1n avertical position in a water saturated atmosphere at a relatively hightemperature until said coating is set.

In testimony whereof, I 'have hereunto set my hand.

EUGENE L. CHAPPELL.

